URL Syntax

URLs
provide a means of locating any resource on the Internet, but these
resources can be accessed by different schemes (e.g., HTTP, FTP,
SMTP), and URL syntax varies from scheme to scheme.

Does this mean that each different URL scheme has a radically
different syntax? In practice, no. Most URLs adhere to a general URL
syntax, and there is significant overlap in the style and syntax
between different URL schemes.

Most URL schemes base their URL syntax on this nine-part general
format: